(5a) Characterizing Water in Oil Emulsions with Application to Methane Hydrate Formation

Water in oil emulsions have significant applications during the production and processing of crude oil. The ability to predict and measure drop size distributions is important for developing effective flow assurance strategies. Specifically, water in oil emulsions are particularly important regarding methane hydrate blockages during crude oil production. The drop size distribution of the emulsion, and the relationship between drop size and methane hydrate formation are significant when mitigating methane hydrate blockages. Currently, there are speculations about the exact structure of water drops during hydrate formation, and this is propagated by the paucity of water droplet size measurements in crude oils.

This work utilizes nuclear magnetic resonance to directly measure emulsion properties of both model and crude oils. Nuclear magnetic resonance is particularly useful for these systems because it is not constrained by the optical properties of the systems, and it considers the entire emulsion. Specifically, drop size distributions are obtained for both crude oil and model oil emulsions using the pulsed field gradient with diffusion editing (PFG-DE) technique. This technique is useful for directly measuring drop size distributions because it does not assume a form of the drop size distribution. A one dimensional imaging technique is also employed that yields quantitative information about the spatial distribution of components in the emulsions. Finally, transverse relaxation measurements are used to directly measure the conversion of water to methane hydrate. This work provides quantitative information that describes the structure of water droplets during methane hydrate formation. In addition, this work provides insight about the mechanisms that govern drop breakup in crude and model oil emulsions.